3. Shape of an object is a definite aid in your identification process
because one of the first things you must do is determine whether the object
is natural or manmade (Figure 1-16). Natural terrain features are irregular
in shape, but manmade objects have very regular geometric patterns with
straight lines and regular curves. Using this knowledge, the IA can quickly
scan a series of images and eliminate the irrelevant from the relevant,
distinguish cultural features from those of military significance, and
devote attention to the important areas. The importance of shape is further
emphasized when we realize the enemy's camouflage efforts are primarily
directed toward breaking up the shape of enemy installations and equipment.
The pictorial effect and analysis of vertical images are
greatly influenced by shadows (Figure 1-17).
The shape of an object is
often more discernible from the shadow it casts than from its vertical (top)
view. By studying the vertical image of an object together with its shadow,
you can learn to associate the vertical appearance of that object with its
angular side view as represented by the shadow. This should enable you to
form a mental image of the object as it would appear from the ground. An
excellent example is a bridge, the shadow of which frequently reveals the
construction of a bridge's supporting structure.
Also, shadows allow the
identification of electronic installations by revealing their characteristic
a. Shadows also aid in the penetration of camouflage which might
otherwise successfully conceal some installations.
Even fake shadows
employed in camouflage can be easily detected on aerial photos. Camouflage
shadows are usually painted on the ground and appear in a true position with
relation to the sun at only one time of the day. Thus, shadows painted to
appear true in the morning will be completely out of position in the
b. Shadows also aid in the orientation of an image with a map as,
depending on the time of day, the shadows fall generally toward the north
(between NW and NE) in the northern hemisphere.
c. Shadows can hide objects as well.
A tank parked in the shadow of a
building or tree can be overlooked by the IA who doesn't pay attention to
such details as tank tracks leading up to, but not away from, the building